With the development of mobile data networks such as 3G/LTE (Long Term Evolution)/WiFi and the widespread use of smart handheld terminals such as cell phone/tablet PC, various mobile data services develop rapidly, which rapidly promotes the mobile data network from hotspot coverage to hot-zone coverage. Thus, supporting the IP mobility in the hot zone to maintain the user experience has become an indispensable function of the mobile data network.
Currently the WLAN (wireless local area network) uses the base station+base station controller, namely AP+AC (AP Controller), star structure. When a terminal switches between the APs (Access Points), the maintenance of its identity information and the switch of data channel are charged by the AC. With the deployment of 802.11ac products, the air interface rate is about to enter into the era of 1 Gbps. If continuously using the AP+AC star structure, the AC will be under enormous pressure of data forwarding because one AC is generally responsible for managing dozens of to thousands of APs, which has a very high requirement on their routing and forwarding performances, and becomes the data bottleneck. Meanwhile, the bearer network still needs high-performance switches and routers to transmit data. Thus, the service network and the bearer network will form two overlapped networks, this overlapping architecture increases not only the forwarding delay but also the management complexity and failure probability, which even greatly increases the network construction and maintenance costs.
The IP field uses the MIP (Mobile IP) protocol to support the IP mobility, and this protocol requires the client's support and has the triangular routing efficiency problem. To this end, a (Proxy Mobile IP) protocol is developed to let the network side take the entire responsibility for supporting the IP mobility.
As shown in FIG. 1, the PMIP protocol has the MAG (Mobile Access Gateway)+LMA (Local Mobility Anchor) star structure. In the case that the data traffic surges, the LMA becomes the data bottleneck. Besides of requiring both the router and the radio access point supporting the PMIP protocol, its network architecture still forms two overlapped networks of the service network (MAG/LMA supporting the IP mobility) and the bearer network.
The 3GPP (3rd Generation Partnership Project) also uses the terminal-led DSMIP (Dual Stack Mobile IP) protocol whose nature is similar to the MW protocol and which supports the IPv4 and v6. The terminal initiates the DSMIPv6 signaling in the control plane: the MIPv6 signaling may be encapsulated and sent in the IPv4 tunnel. In the data plane, the terminal maintains the data tunnel to the PDN (Public Data Network) GW (Gate Way), and the user data flow is directly forwarded by the terminal to the PDN GW via the GRE (Generic Routing Encapsulation) tunnel. All the above is the overlay network architecture of service network and bearer network.
When a terminal switches between various ports of a router, the current router technology is already able to assign the same IP address to it, but it requires the terminal initiating a DHCP (Dynamic Host Configuration Protocol) process to refresh the data routing of the router and its switch. The DHCP is time-consuming, and the terminal frequently initiating the DHCP is not necessary and also increases the network payload when the switch is frequent. Moreover, for a user using the static fixed IP address, the DHCP process will never be initiated. Before refreshing the ports of the routing/switching table, data sent to the terminal that after the switch will not be properly arrived. This will lead to service discontinuity, even service interruption, after the terminal switches, which severely degrades the user experience.
The currently popular SDN (Software defined network) uses the network architecture in which the control and forwarding are separated, but it does not support the WLAN terminal moving because it does not involve the WLAN network.